SAT-ZIP

Fast desktop archiver with its own codec

SAT-ZIP started with one question: how fast can an archiver be if the codec is built for speed from the ground up? The answer became a complete Windows app around a codec of my own.

DownloadChecking latest release

Source code

C++
AVX2
Dear ImGui
CMake
Inno Setup

2.2 GB/s: decompression speed on text, native build
1.4x: faster than LZ4 at decompressing text
5: archive formats it reads and writes
3: compression modes, from fast to max ratio

The story

01
Why another archiver
Zipping in Windows is slow and easy to forget about. I wanted an archiver with LZ4-class speed that people can actually use every day: right-click a folder, pick a format, done. And because speed claims are cheap, it ships with a benchmark lab so anyone can measure it on their own files.
02
The codec
Data is cut into independent 64 KiB blocks. A hash table finds repeated sequences, and the decoder copies matches with wide SIMD loads. In my benchmarks the decoder beats LZ4 on text (2229 vs 1552 MB/s) and on mixed data (2622 vs 2385 MB/s). Every number is checked against a decode of the same data before it is reported.
03
Three modes
Mode S uses a single-probe hash table and is the fastest. Mode R adds hash chains and lazy matching for a better ratio, with the same decode speed. Mode T puts a split-stream rANS entropy coder on top for the best ratio. All three share one block format.
04
More than a codec
Around the codec sits a full app: multithreaded .zip, plus .7z, .tar and .tar.xz, an Explorer right-click menu, a command-line tool and a C SDK. Archives can optionally be encrypted with SAT-OBELISK.

Live demo

Compress it in your browser

This is the real SAT-ZIP codec, compiled to WebAssembly (10.6 KB). Type some text or drop a file. Everything runs on your device; nothing is uploaded.

Input

{
  "eyebrow": "Projects",
  "title": "Things I built.",
  "intro": "Personal projects, from low-level codecs to complete desktop apps. Public projects have a direct download of the latest release.",
  "sourceCode": "Source code",
  "download": "Download",
  "downloadVersion": "Download {version}",
  "checking": "Checking latest release",
  "notPublic": "Not public yet",
  "youAreHere": "You're literally on it",
  "items": {
    "satZip": {
      "tagline": "Fast desktop archiver with its own codec",
      "description": "A Windows archiver powered by a custom high-throughput LZ codec whose decompression beats LZ4. Reads and writes .satz, .zip, .7z, .tar and .tar.xz, integrates into the Explorer right-click menu and ships with a built-in benchmark lab."
    },
    "satObelisk": {
      "tagline": "A small sponge-based cryptosystem",
      "description": "Built on one 384-bit permutation: authenticated encryption, hashing, key derivation, key wrapping and file encryption. A research and teaching project, not a replacement for audited crypto."
    },
    "satExplorer": {
      "tagline": "A faster, more original file explorer",
      "description": "A Windows file explorer in the spirit of Total Commander, built to match the built-in Explorer while being faster. Strict layering between the engine and the UI, native Win32 enumeration, git and SVN status columns and themes."
    },
    "satSans": {
      "tagline": "My own typeface, used on this site",
      "description": "A geometric UI font with squircle curves, obelisk-cut stems and diamond dots, plus a monospace variant for code. This font is used across this entire website."
    },
    "thiersLabs": {
      "tagline": "This website",
      "description": "Static Astro site with React islands, two languages and live release info from GitHub, hosted on my own Debian server behind Caddy."
    }
  },
  "kofi": {
    "title": "Like what I make?",
    "text": "Everything here is built in my own time. If a project helped you, a coffee keeps the next one going.",
    "button": "Support me on Ko-fi"
  },
  "detail": {
    "back": "All projects",
    "factsTitle": "At a glance",
    "storyTitle": "The story",
    "moreTitle": "More projects",
    "explore": "Explore and try it live",
    "metaTitle": "{name} - ThiersLabs"
  },
  "details": {
    "satZip": {
      "intro": "SAT-ZIP started with one question: how fast can an archiver be if the codec is built for speed from the ground up? The answer became a complete Windows app around a codec of my own.",
      "facts": [
        {
          "value": "2.2 GB/s",
          "label": "decompression speed on text, native build"
        },
        {
          "value": "1.4x",
          "label": "faster than LZ4 at decompressing text"
        },
        {
          "value": "5",
          "label": "archive formats it reads and writes"
        },
        {
          "value": "3",
          "label": "compression modes, from fast to max ratio"
        }
      ],
      "sections": [
        {
          "title": "Why another archiver",
          "text": "Zipping in Windows is slow and easy to forget about. I wanted an archiver with LZ4-class speed that people can actually use every day: right-click a folder, pick a format, done. And because speed claims are cheap, it ships with a benchmark lab so anyone can measure it on their own files."
        },
        {
          "title": "The codec",
          "text": "Data is cut into independent 64 KiB blocks. A hash table finds repeated sequences, and the decoder copies matches with wide SIMD loads. In my benchmarks the decoder beats LZ4 on text (2229 vs 1552 MB/s) and on mixed data (2622 vs 2385 MB/s). Every number is checked against a decode of the same data before it is reported."
        },
        {
          "title": "Three modes",
          "text": "Mode S uses a single-probe hash table and is the fastest. Mode R adds hash chains and lazy matching for a better ratio, with the same decode speed. Mode T puts a split-stream rANS entropy coder on top for the best ratio. All three share one block format."
        },
        {
          "title": "More than a codec",
          "text": "Around the codec sits a full app: multithreaded .zip, plus .7z, .tar and .tar.xz, an Explorer right-click menu, a command-line tool and a C SDK. Archives can optionally be encrypted with SAT-OBELISK."
        }
      ],
      "demoTitle": "Compress it in your browser",
      "demoIntro": "This is the real SAT-ZIP codec, compiled to WebAssembly (10.6 KB). Type some text or drop a file. Everything runs on your device; nothing is uploaded.",
      "demoEyebrow": "Live demo"
    },
    "satObelisk": {
      "intro": "SAT-OBELISK is a complete cryptosystem built from one primitive: a 384-bit permutation I designed. It is a research and teaching project, and it is honest about that.",
      "facts": [
        {
          "value": "384-bit",
          "label": "permutation state, six 64-bit lanes"
        },
        {
          "value": "16 / 10",
          "label": "rounds for setup and for data"
        },
        {
          "value": "128-bit",
          "label": "security target"
        },
        {
          "value": "3",
          "label": "rounds until full diffusion"
        }
      ],
      "sections": [
        {
          "title": "One permutation, everything",
          "text": "Like Ascon, the winner of NIST's lightweight cryptography competition, OBELISK uses a sponge and duplex construction. One permutation gives authenticated encryption, hashing, key derivation, key wrapping and file encryption. Taming one primitive well is safer than combining four mediocre ones."
        },
        {
          "title": "Inside the permutation",
          "text": "The state is six 64-bit lanes. Each round mixes them with ARX boxes (add, rotate, xor) and a linear layer of rotations. The round constants come from the digits of pi, so there is nowhere to hide a backdoor. Setup and hashing use 16 rounds, data processing uses 10."
        },
        {
          "title": "Honest about security",
          "text": "The custom cipher has never been independently reviewed, so it is not for real secrets. For real data the app uses vetted backends, ChaCha20 or AES-256-GCM. Instead of claiming it is unbreakable, the repository invites anyone to break it, and reduced-round attacks count too."
        },
        {
          "title": "Measured, not assumed",
          "text": "Avalanche tests, known-answer tests and tamper tests check the design. A single changed input bit flips about half of the output bits, and full diffusion is reached after only three rounds. The weak spots are documented next to the strong ones."
        }
      ],
      "demoTitle": "Hash and encrypt in your browser",
      "demoIntro": "This demo runs the real OBELISK Python code in your browser with Pyodide. Starting it downloads a Python runtime of about 10 MB, once. Nothing you type leaves your device.",
      "demoEyebrow": "Live demo"
    },
    "satExplorer": {
      "intro": "SAT Explorer is my own Windows file explorer: all the features of the built-in one, but faster, with tabs and split panes, and a look that adapts to the machine it runs on.",
      "facts": [
        {
          "value": "3",
          "label": "layers, dependencies in one direction only"
        },
        {
          "value": "4",
          "label": "quality modes, picked from your GPU"
        },
        {
          "value": "0",
          "label": "lines of WPF in the engine"
        },
        {
          "value": ".NET 10",
          "label": "C#, WPF and MVVM"
        }
      ],
      "sections": [
        {
          "title": "Why build a file explorer",
          "text": "I spend all day in folders, and the built-in Explorer often makes me wait. I wanted something in the spirit of Total Commander: split panes, tabs, custom commands and columns such as git and SVN status, with every feature of the original still there."
        },
        {
          "title": "Core and skin",
          "text": "The app is three layers: App (the WPF interface), Core (the engine) and Shell (the Win32 calls). Dependencies only point down. The engine never touches WPF, and the look lives in swappable skins, so a feature built once in Core works in every skin."
        },
        {
          "title": "Speed pillars",
          "text": "Folders are read with native FindFirstFileEx calls instead of the slower .NET helpers. All reading happens off the UI thread and navigation can be cancelled, so fast clicking never piles up. The file list is virtualized, so only the rows on screen are ever drawn, no matter how big the folder is."
        },
        {
          "title": "Scales with your hardware",
          "text": "On start-up the app checks how well the GPU can render. A gaming PC gets shadows, rounded corners, animations and live thumbnails. An old laptop or a remote desktop gets a flat, instant interface. One build, no separate lite version."
        }
      ],
      "demoTitle": "Inside the app",
      "demoIntro": "A real screenshot of SAT Explorer: two panes with their own tabs, quick access, drives and a toolbar for everyday file work. A few personal folder names were changed before publishing.",
      "demoEyebrow": "Screenshot",
      "screenshotAlt": "SAT Explorer with two panes side by side, a sidebar with quick access and drives, and a toolbar",
      "openFull": "Open full size",
      "layersTitle": "Who does what",
      "layers": [
        {
          "name": "App",
          "text": "WPF windows, skins and quality detection"
        },
        {
          "name": "Core",
          "text": "Engine: models, services, view models. No WPF"
        },
        {
          "name": "Shell",
          "text": "Win32 calls: enumeration, icons, context menus"
        }
      ]
    }
  }
}

Drop a file anywhere in this box

More projects

SAT-OBELISKA small sponge-based cryptosystem

SAT ExplorerA faster, more original file explorer